Heretofore, for the residential class of diaphragm gas meters, the industry standard method for retrofitting one of these meters with an Automatic Meter Reading (AMR) device has been to install the conventional AMR module 112 between the main body of the gas meter and the gas meter's index (register) as shown in FIG. 2-FIG. 4. The index (register) is a mechanical clock work type assembly that is fairly delicate so as to allow it to be driven by and count revolutions of a gas meter shaft that is internally driven by the flow of natural gas or propane through the meter. Similar technology and the associated problems and limitations apply to water utility meters. Electric utility meters, which include or have an available electrical energy supply may also suffer from some of the same problems and limitations as those described for gas meters.
This basic conventional process for retrofitting a conventional AMR device may typically involves the following primary steps. Certain minor steps that may readily be appreciated in conventional retrofit operations are not described to prevent obscuration of the primary steps.
First, the gas meter's index cover is removed from its attachment to the meter over the meter index (register). The index cover is conventionally a simple transparent plastic cover that allows a visual reading of the meter index dials and pointers, and that protects the meter index mechanism.
Second, the delicate mechanical clock work type index assembly is removed from the meter including disengaging the index assembly from its driving gas meter shaft which will continue to rotate if any gas is being consumed. Thus, it is necessary to carefully align the index drive mechanism while the index drive is turning when it is reinstalled, which may tend to cause a misalignment of the keyed shaft with the index assembly.
Third, with the original index still removed from the gas meter, the original index is attached to or mounted onto the conventional AMR module. In known examples of conventional AMR retrofit assemblies and methods, the conventional AMR unit is attached to the back side of the conventional index so that when reassembled, the conventional AMR unit is located between the gas meter body and the original index. This placement at least somewhat diminishes the performance of any radio frequency transmitter or receiver device as the metal of the meter body and the metal of the index tends to shield, attenuate, or block some of the radio frequency signals. Furthermore, the RF antenna that may be provided in the conventional AMR unit may have diminished performance do to the adjacent metallic surfaces and structures.
Fourth, the combined index and conventional AMR assembly is placed onto the meter body, with care being taken to realign the keyed meter shaft (which may be rotating if there is any gas flow). There may also be a possibility that the portion of the index receiving the gas meter shaft was moved or rotated either from handling or to fit it to the AMR unit.
Finally, the index cover or a replacement cover sized to accommodate the volume of the combined AMR unit and index is installed.
It may be noted that when the conventional AMR unit battery requires replacement, at least the index cover needs to be removed thereby again exposing the index and AMR unit to current environmental conditions such as dust, rain, ice, or snow. Depending upon the design of the particular conventional AMR unit, removal of the index cover, index, and AMR unit, may be required to access the battery as well as to perform any service or replacement of the electronics portion of the AMR unit.
Some additional problems and limitations created by this conventional methodology, and by the physical and operational limitations of the AMR module in addition to those already described include: First, the number of steps involved in this conventional retrofit process causes a high labor cost and relatively high skilled technician to perform the tasks without damaging the original or retrofit equipment.
Second, assembly errors can occur during the assembly of the index onto the conventional AMR module and the re-assembly of the conventional AMR device with the index and the combined assembly to the gas meter. If either of these occurs the meter's index no longer accurately tracks the flow of gas through the meter or the customer's gas consumption because of the improper realignment of the index drive mechanism. The removal and replacement may also be susceptible to introducing an error or offset to the actual meter reading. These kinds of errors can go undetected for an extended period of time resulting in lost revenue or over charges by the utility company, additional labor costs to correct the problem at the customer site, as well as possible customer relations problems.
Third, once the conventional AMR module is attached to the gas meter, it is extremely difficult, if not impossible, to change the AMR module's battery in the field, as the above described installation procedure must be reversed and then repeated. These operations will be performed with a unit that has been installed for months or years and with the accumulated dirt on the unit. Either this will all need to be cleaned prior to disassembly and reassembly, or there is significant chance of contaminating the assembly, particularly the clock work type index.
Fourth, the radio frequency (RF) characteristics for the conventional AMR module are poor because it is mounted between the meter, which is made of aluminum, and the meter's index, which is made either of plastic, aluminum or brass and usually includes at least some aluminum or brass components even when plastic in part. Depending upon the radio frequency characteristics of the conventional AMR module radio and the location of a receiver/transmitter for the conventional AMR signal, the aluminum meter and any aluminum, brass, or other metal may severely reduce the ability of the AMR to send or receive radio frequency signals.
Attention is now directed to a conventional gas meter and the procedure in which a conventional AMR device and its retrofit installation has conventionally been achieved.
FIG. 1 is an illustration showing a typical conventional utility gas meter 101 before a conventional AMR retrofit, such as a meter made by the American Meter Company (also known as Elser American Meter, 2221 Industrial Road, Nebraska City, Nebr. 68410 USA). The gas meter includes a gas meter body portion 104 having inlet 105 and outlet 106 plumbing connections, and a meter index 108 covered by a meter index cover 110. The meter index is the portion of the meter 101 that counts and indicates the amount of gas used and is conventionally a rotating clock work type mechanism, wherein the flow of gas through the meter causes a shaft to rotate and the rotation of the shaft which extends to an exterior of the meter body interacts with the meter index. Rotation of gears and dials of the meter index is indicated as a meter index readout. These conventional meter indexes are known in the art and not further described here.
With reference to FIG. 2-FIG. 4, we now describe a conventional industry solution for gas meter retrofit solution as used in the gas metering industry prior to the invention described herein.
With reference to FIG. 2a-FIG. 2c, first the index cover 110 and then the index 108 is removed from the meter body 104.
With reference to FIG. 3a-3b, second, assemble the meter's original index 108 to the AMR module assembly 112 including the AMR module 114 and new AMR module cover 116, being very careful to properly align the meter index drive mechanism between the conventional AMR module 114 and the meter's index 108. If this is not done properly the meter index 108 may be damaged and/or an inaccurate reading will result. Likewise, an inaccurate reading caused by improper alignment or installation may result in contention that the meter reading is inaccurate and an inability to collect for gas consumption.
With reference to FIG. 3c, third, mount the fully assembled AMR module assembly 114 with meter index 108 and the new AMR module cover 116 on the gas meter 101, being very careful to properly align the index drive mechanism (typically a keyed drive shaft) between the meter 108 and the AMR module 114. Again, if this is not done properly the meter index may be damaged and/or an inaccurate reading will result.
With reference to FIG. 4, fourth reattach the index cover 116 which will usually be a replacement cover adapted to cover the increased depth of the original meter index 108 and the added depth of the retrofit AMR module 114. The conventionally retrofitted meter 130 is illustrated in FIG. 4 and shows the conventional AMR module located under the index cover between the meter body 104 and the original index cover 116. It may be appreciated that some of these steps may be combined or divided in different ways.
It will be apparent that the conventional retrofit involves significant disassembly and reassembly steps that require a relatively skilled technician. These retrofit steps are even more problematic since they are conducted in the field, possibly with old and weathered meters, dust or rain in the air, cold temperatures, and other contaminant and environmental challenges. In the event a part is damaged during disassembly or reassembly, the meter may be rendered completely inoperative until replacement parts can be obtained and installed in addition to the AMR module. The size of the AMR module is also significant and increases the size of the index cover and its extension in the local environment potentially making it more vulnerable to damage.